This application relates to the production of zeolite-like gallosilicates.
Zeolite-like gallosilicates can be represented by the formula EQU (M.sup.n+).sub.x/n [(GaO.sub.2).sub.x (SiO.sub.2).sub.96-x ]
wherein M stands for an alkali-metal or alkaline-earth metal of valence n and x may assume non-zero values of up to 10. Like other zeolites, such zeolite-like gallosilicates belong to the class of tectosilicates. Their structure consists of TO.sub.4 tetrahedra, with each oxygen atom being coordinated with two T-atoms. The nature of the T atom is variable, and may be a trivalent atom such as aluminum or gallium as well as the basic quadrivalent silicon.
The TO.sub.4 tetrahedra form chains and strata, and build up a well defined system of cavities, passages or pores with apertures of regular molecular dimensions. These apertures determine the accessibility of the interior of the zeolite to substances according to their shape and form and thus impart separatory properties to the porous zeolite material. When alkali-metal or alkaline-earth metal ions are replaced after synthesis with protons, effective heterogeneous acid catalysts are obtained.
Zeolite-like gallosilicates are especially suitable for use as catalysts in the petrochemical industry and for production of valuable organic intermediates. In particular, owing to their dehydrogenating and aromatizing properties, they find application in the conversion of lower alkanes and alkenes, still often simply burned off today, into higher aliphatics, cycloaliphatics and especially simple aromatics. Aromatics such as benzene, toluene or xylene are important starting materials for numerous syntheses in the manufacture of synthetic fibers, polyesters and other plastics. They are also employed as octane-enhancing substances in unleaded gasoline.
Previously known methods of producing zeolite-like gallosilicates require structure-guiding or structure-stabilizing organic compounds. As a rule these are amines, which apart from the cost factor, may represent a not inconsiderable environmental hazard. Organic hydrocarbons have also been used for this purpose. The object of the present invention is to offer an environmentally sound, non-energy-intensive and economical method of producing gallosilicates having catalytic properties and/or a molecular sieve character.